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Ganymede Simulation
This is a simulation of what one would expect to find on a terraformed Ganymede, using formulas from Math And Terraforming. Please note that not even the supercomputers at NASA can provide us with a perfect simulation. The information showed here is only an approximation. Basic data *Distance from Sun: 778.57 million km *Distance to Jupiter: 1.07 million km *Diameter: 5268 km *Solar Constant: 0.073 *Mass: 0.025 Earths *Mean density: 1.936 kg/l *Orbital period: 7.155 Earth days *Jupiter's orbital period: 11.862 Earth years *Rotation axial tilt: below 10 degrees Atmosphere See Atmosphere Parameters Ganymede is at a safe distance from Jupiter. Its Hill sphere is larger and perturbations from other moons and Jupiter itself are not so strong. This will ensure a more stable atmosphere. During this simulation, we will use an atmosphere with the same pressure at sea level as Earth's and a similar composition. *Atmosphere stability for oxygen molecules: **Earth's gravity (15 degrees C): 4.116 **Ganymede's gravity (15 degrees C): 16.73 **Ganymede's gravity (-100 degrees C): 10.06 *Atmosphere stability for water molecules: **Earth's gravity (15 degrees C): 7.320 **Ganymede's gravity (15 degrees C): 29.75 **Ganymede's gravity (-100 degrees C): 17.88 *Atmosphere stability for hydrogen molecules: **Earth's gravity (15 degrees C): 65.88 **Ganymede's gravity (15 degrees C): 160.9 **Ganymede's gravity (-100 degrees C): 267.8 notes: A value below 10 means stability for over a million years, a value between 10 and 100 means stability between 0.1 and 10 millions of years, while a value higher then 100 means stability for less then 10 thousand years. This calculation does not include solar wind erosion. Conclusion: Above the greenhouse gas layer, Ganymede can hold oxygen for a long period of time, but not for millions of years. Water vapors, which are lighter, might reach to the top of the atmosphere. However, because of the low temperatures, almost all water will condense and will fall back. Ganymede is protected by Jupiter's magnetosphere. However, the little UV radiation that reaches the surface can dissociate water molecules. Hydrogen will be lost into space. The atmosphere will look like this: Ground average temperature: 15 degrees C *Surface pressure at sea level: 1 *Atmosphere total mass (Earth = 1): 1.09 *Atmosphere breathable height: 53.9 km *Atmosphere total height: 161 km Ground average temperature: -100 degrees C *Surface pressure at sea level: 1 *Atmosphere total mass (Earth = 1): 0.85 *Atmosphere breathable height: 41.5 km *Atmosphere total height: 124 km Combined: Atmosphere total mass (Earth = 1): 0.97 Atmosphere breathable height: 47 km *Atmosphere total height: 143 km. Basically, there will be two different atmospheric layers: below and above the greenhouse gasses. The lower layer will be hotter and will contain most of the air, while the upper layer will be cold and will compress the lower layer. The atmosphere will be fluffy. Temperature Main article: Temperature. The first problem with Ganymede is that we need to gain the correct surface temperature. The Solar Constant is low (0.073), compared to Earth (1.98). Greenhouse Gases are needed. The Greenhouse Calculator provides us with some useful values. The needed amount of sulfur hexafluoride is 0.189 kg/sqm. Climate Simulation Main article: Climate. On Earth, the average temperature is +15 degrees C. By using greenhouse gasses we will try the best to get a similar value. Ganymede has a smaller diameter then Earth (0.413), a thing that will help air currents mix temperatures. The extremely fluffy atmosphere also helps us maintain a global temperature similar for the whole moon. Average temperatures for each latitude: *poles: 11 C *75 deg: 13 C *60 deg: 14 C *45 deg: 15 C *30 deg: 16 C *15 deg: 16 C *equator: 17 C Day - night cycle variation: Ganymede has a long day (7.155 Earth days). Because of this and the huge greenhouse effect needed, there will be very little differences in temperature. *Daily temperature variation: 6 degrees C *Equator day-night variations: 14 to 20 degrees C *Near pole day-night variations: 8 to 14 degrees C. Altitude: Because of the fluffy atmosphere, temperature will not decrease significantly with altitude. Seasons: Ganymede has a very small axial tilt, so there will be no seasons. Conclusion. Ganymede is very interesting. It behaves like an Outer Planet, but, unlike Io and Europa, it has temperature variations. The poles are about 6 degrees C colder then the equator. Day - night temperature variations exist because of the long day cycle. Overall, there will be temperature differences up to 12 C. This can slightly influence the hydrologic regime. We can expect during day humidity to decrease a bit and even to see sometimes corners of blue sky, while in night, it will rain more often. Geography See also: Geography and Geographic Pattern - Tectonic. Ganymede is very complex, with mountains, craters and fractures. The moon appears to have a thick icy crust that covers a subsurface ocean. In such conditions, three terraforming solutions are possible, each one with its own advantages and problems. *Melt the ice and build an Oceanic Planet. This will take time because the crust is thick. *Build Artificial Continents. This solution requires first that the icy crust will be melted. The subsurface ocean is not too active and continents might be stable. *Cover the ice with Ground Insulation. This solution requires much work and is expensive. Oceans. If we melt the crust, the subsurface ocean will be exposed. For Ganymede, we know nothing about the chemical composition of its interior ocean. If it is too salty, we will create a Salt Ocean Planet, which cannot support much marine life. Continents. If artificial continents will be built, they will not have high mountains, to save resources. They might have lakes and rivers. It is possible that the continents will be small. However, if we find out that the ocean has toxic chemical compounds, we can cover much of the ocean surface with floating materials used for the continents. This will reduce evaporation rates of unwanted chemicals. The Sky As one can see above, the atmosphere of Ganymede will be fluffy. Clouds and hazes will block visibility. It is possible that settlers will see blue sky only on occasions. Still, assuming sky visibility similar to Earth, one will see the following celestial bodies: *The Sun - 1.79 units *Jupiter - 130.7 units *Io - 2.43 to 5.60 units *Europa - 1.79 to 7.82 units *Calisto - 1.63 to 5.93 units. No other moon will be visible even as a star. To see how large a celestial body will look like, draw a circle of X mm on a sheet of paper and look at it from a distance of 1 m. *Mercury: 3.2 to 3.6 magnitude *Venus: 0.2 to 0.8 magnitude *Earth: 1.3 to 2.2 magnitude **Moon: 5.2 to >6 magnitude *Mars: 4.2 to 5.5 magnitude *Saturn: 1.2 to 3.8 magnitude Human Colonies *Population limit: 31.6 million *Land population feeding capacity: 11 people fed from one square km *Largest city supported by environment: 130 000 people Assuming it will have similar types of terrain Earth will have, Europa can support a Population Limit of 31.6 million people. If Ganymede will be an oceanic planet, we can imagine some large floating cities roaming on its surface. Also, if artificial continents will be built, there is a high chance that they will be small, concentrating the population. Industry Ganymede is close to Io, which is rich in metals and many ores required for industry. Also, it is close to Europa, which has many salts in its ocean. This can be used as an advantage. Ganymede can become an important industrial player in the Outer Solar System. Being the largest moon of Jupiter, it can support the largest population and the biggest cities. Also, it will experience much smaller quakes then Io and Europa. Agriculture Ganymede is far from the Sun. Because of this, plants don't get enough light to grow like on Earth. Still, settlers will have to produce the food they need to eat. Experiments made with grain crops showed that at Jupiter's orbit, it is possible to grow and harvest cereals (see Plants on new worlds and Agriculture for details). Transportation Ganymede has a less powerful volcanic activity. Therefore, building an infrastructure is possible on the moon. Roads and railways can be built on the continents, to create local transport network. However, for long distances, ocean and air transport will be more feasible. Orbits around the moon appear to be stable for enough time. A network of satellites can provide the background for telecommunications. It is impossible to launch a satellite into a geosynchronous orbit, so there will be many satellites orbiting the moon. There will be one or more bases on the surface, that will be used for spaceships. Most interplanetary ships will dock at Himalia, while cargo and passengers will be transshipped to and from Ganymede by smaller ships. Tourism Because it will have some temperature variations, Ganymede will not have humidity close to 100%. Because of this, the moon will be more attractive to settlers. We yet don't know what touristic attractions will be on the moon. Wild Life Ganymede can support plants and animals from a wet temperate climate. Forests can exist on the surface of the moon. Category:Simulation Category:Math